A wave simulation system (also called a wave maker system) is an essential environment simulation device in an ocean engineering laboratory. Regular waves and irregular waves can be generated mutually in limited pools and tanks of the laboratory through use of the wave maker, so as to provide a simulation environment of experimental verification for development of marine equipment.
When wave maker is used for wave simulation, an experimenter firstly sets wave parameters according to a target spectrum; then, the motion curve of each wave making paddle is calculated according to a system transfer function, and a corresponding control signal is generated; next, the information is transmitted into a controller; subsequently, the controller controls a servo axis connected with the controller to move according to the received motion information; and finally, the wave making paddles move back and forth under the drive of the servo axis, thereby producing waves of different forms. It is observed from this process that the precision of wave simulation completely depends on the precision of control over wave making motion. However, the wave making process is a linkage process of a plurality of wave making paddles. The motion value of each wave making paddle is a discrete sampling point of the wave making motion curve in spatial distribution. In addition, not all of the wave making paddles in a multi-plate wave maker are operated under one clock, i.e., a precision problem of synchronous control exists in the motion process of the wave making paddles.
To solve evaluation problem of the motion control performance of the wave making paddles in the development process and the wave making experimentation process of the wave maker, a method of human eye observation and a method of a laser displacement sensor are often adopted in practice. Both of the methods can partially solve some site test and evaluation problems, but have great problems in time control precision, quantity of wave making paddles to be measured simultaneously, experiment measurement cost and convenience (degree of operation. Therefore, a measurement method and apparatus applied to a multi-plate wave simulation system is urgently needed to synchronously acquire instant position information of all the wave making paddles in real time. An image measurement method has the characteristics of high precision, no disturbance, full-field measurement and visual information. In addition, an image measurement system constructed after integrating the technology with an EtherCAT data acquisition technology not only has the characteristic of the image measurement technology, but also has the characteristics of simple site wiring, large range of field of view, convenient installation and high data transmission efficiency, and is especially suitable for constructing the motion measurement system of the large multi-plate wave simulation system.